Dear EarthTalk: Could our health be negatively affected by all the radio frequencies being bandied about by cell phones and cell phone towers, wireless pagers and Internet systems, and other uses of radio frequency and microwave radiation?—Name Withheld, Santa Cruz, CA

Since the middle of the last century technological advancements in telecommunications and other industries have led to significant increases in the use of radio frequencies. Equipment employing microwave and radio waves is today widely used not just in broadcasting and communications, but also in the health care industry, the food industry, and in a host of other industries in a wide range of applications.

Health advocates have worried for decades that exposure to frequencies emanating from these many sources might be harmful. And the ubiquity of such technology today—especially considering the quantum leap in cell phone usage in recent years—only makes such concerns that much more pressing.

Various studies researching the health effects of cell phone use have yielded mixed results. Some earlier studies suggested a link between exposure to radiation from cell phones and an increased risk of acoustic neuroma—a cancerous tumor of the nerve connecting the ear to the brain—but more recent research found no such links. The issue is primarily heat. According to the Occupational Safety and Health Department of the Communication Workers of America (CWA), “As high frequency radio frequency radiation penetrates the body, the exposed molecules move about and collide with one another causing friction and, thus, heat. If the radiation is powerful enough, the tissue or skin will be heated or burned.”

According to CWA, “there is substantial scientific data that establishes negative health effects associated with microwave radiation.” CWA cites cataracts as one possible negative health effect from prolonged exposure, as well as well as nervous system damage and even reproductive problems in both males and females. This issue was in the news in 1992 over the issue of the safety of police radar devices, but subsequent studies were inconclusive.

As to cell phones, the results of a study recently published in the academic journal Environmental Health Perspectives do not bode well for habitual chatterers. Researchers documented brain damage in laboratory rats exposed to radio frequencies from cell phones at levels comparable to what people would experience during normal use. The study’s authors expressed concern that “after some decades of (often) daily use, a whole generation of [cell phone] users may suffer negative effects, perhaps as early as middle age.”

The environmental effects of radio frequencies are also largely unclear. Migrating birds have been known to fly right into cell phone and other communications towers. Some blame the radiation emanating from such towers for disorienting the birds and undermining their navigational abilities. Others chalk such incidents up to poor visibility associated with bad weather and nothing more. Some farmers have observed that cows grazing near cell towers are more likely to experience still births, spontaneous abortions, birth deformities and behavioral problems, not to mention general declines in overall health. Moving cattle herds away from such towers has reportedly led to immediate health improvements.

Dear EarthTalk: I recently heard the term “carbon sequestration” in relation to climate change. What is it and how can it help stave off global warming?—Bob Whelan, Pawtucket, RI

Carbon sequestration is simply the intake and storage of the element carbon. The most common example in nature is during the photosynthesis process of trees and plants, which store carbon as they absorb carbon dioxide (CO2) during growth. Because they soak up the carbon that would otherwise rise up and trap heat in the atmosphere, trees and plants are important players in efforts to stave off global warming.

Environmentalists cite this natural form of carbon sequestration as a key reason to preserve the world’s forests and other undeveloped lands where vegetation is abundant. And forests don’t just absorb and store large quantities of carbon; they also produce large quantities of oxygen as a by-product, leading people to refer to them as the “lungs of the earth.”

According to the Western Canada Wilderness Committee, the billions of trees in the boreal forest of the northern hemisphere that stretches from Russian Siberia across Canada and into Scandinavia absorb vast amounts of carbon as they grow. Likewise, the world’s tropical forests play an important role in naturally sequestering carbon. As such, environmentalists see preserving and adding to the world’s forest canopy as the best natural means for minimizing the impact of global warming caused by the 5.5 billion tons of carbon dioxide generated by factories and automobiles each year.

On the technological front, engineers are hard at work developing man-made ways to capture the carbon spewing from coal-fired power plants and industrial smokestacks and sequester it by burying it deep within the Earth or the oceans. The Bush administration has embraced carbon sequestration as a means to mitigate U.S. carbon dioxide emissions and is spending upwards of $49 million annually on research and development, hoping that the technology might play an important part in keeping greenhouse gas emissions out of the atmosphere. The U.S. is also funding related research in China in hopes of stemming the tide of Chinese CO2 emissions that are increasing quickly as that nation develops rapidly (China has already surpassed the U.S. as the largest coal consumer).

The Bush administration refused to sign onto the Kyoto Protocol, an international agreement adopted in Japan in 1997 calling on countries to limit their emissions of greenhouse gases. Instead, many environmentalists feel, they are pursuing carbon sequestration technology as a quick fix or “Band-Aid” approach that enables them to preserve the existing fossil fuel infrastructure instead of replacing it with clean renewable energy sources or efficiency gains. Essentially the technology involves disposing of carbon dioxide after it is produced, rather than trying to hold down its production in the first place. United Nations” studies suggest, however, that it might play a bigger role in fighting global warming this century than any other measure.